1. Field of Invention
The present invention relates to a collecting apparatus. More particularly, the present invention relates to a collecting apparatus with a power system for collecting large quantities of nanoparticles.
2. Description of Related Art
For the past two decades, nanotechnology research has brought significant breakthroughs and accumulated abundant observations, especially regarding chemical materials, manufacturing, electronic information, medicine, biochemistry, environmental protection, and power generation.
The invention of the steam engine marked the first industrial revolution; and the inventions of electric power, the electric motor and the internal combustion engine marked the second industrial revolution and transcended the millimeter scale. The invention of the computer based on microelectronic technologies marked the third industrial revolution and began to transcend the micrometer scale. Now, innovative nanotechnology is breaking through the nanoscale barriers and leading the fourth industrial revolution.
Nanotechnology is set to create much new matter, materials and machines for the future. Nanotechnology will thoroughly revolutionize human life over hundreds of years and will specifically make huge improvements to the health, wealth and lives of people.
Therefore, most developed countries have invested much human effort and financial and material resources to actively research the field of nanotechnology. Preparative and collection methods of nanoparticles are key technologies in the field of nanotechnology but are plagued by many obstacles to overcome. Scientists all over the world are presently devoting their efforts to break through these technological problems.
Preparative methods of nanoparticles can be approximately classified into physical and chemical methods whose nanoparticle size must be smaller than 100 nm (where 1 nm=10−9 m). How to collect large quantities of nanoparticles in the preparation process is a key problem. Nanoparticles are easily gathered into a big agglutinated body because of their surface activity, and this phenomenon brings great difficulty in collecting them individually. In order to overcome this problem, whether using physical or chemical methods, the nanoparticles are generally allowed to disperse in solution. While sedimenting, large-sized particles first settle to the bottom, leaving nanoscale particles suspended in solution with Brownian movement. Nanoparticles can then be obtained after the water is removed as so-called nanopowder.
Currently, the ultracentrifuge method is mainly used to settle particles. The principle of the ultracentrifuge method is the same as a clothes washing machine, spinning a material to precipitate particles to the bottom according to the centrifugal force and throwing the upper suspensions away to obtain desired particles.
However, finer particles are more difficult to settle, meaning that the fine particles need more time and centrifugal force to become settled. For example, to precipitate nanoparticles of greater than 1 nm diameter within 10 mL of sample, the required centrifuging time is 17.6 hrs at 90,000 rpm (centrifugal force of 470,000×g); to settle nanoparticles of greater than 25 nm diameter, only 119 sec at peak speed is needed.
Although this method can obtain nanoparticles, it consumes much time and cannot collect large quantities of nanoparticles. Thus, this method cannot be employed for industrial mass production.
Filtering using a membrane filter is also used to collect nanoparticles, wherein sample is passed through the membrane filter using hand pressure and drawn into syringe barrel. Membrane filters with pore size of 450 nm are in common use at present, and membrane filters with pore size of under 450 nm are available in 300, 220, 100, 50 and 25 nm sizes according to Millipore, a company specializing in manufacturing membrane filters.
However, the filtering work is harder for smaller pore size, so a pore size of 25 nm is the most difficult to operate. For a 10 mL sample, more than 4 minutes by hand pressure are needed to filter nanoparticles (>25 nm diameter). Moreover, the operator must continue to maintain the pressure by his fingers, so using this filtering method not only is inefficient and collects only low quantities of nanoparticles but also is laborious.